How we cite our quotes: (Chapter.Paragraph)
Quote #7
There is something in the negro which, in a peculiar way, fit him for avocations about one's person. Most negroes are natural valets and hair-dressers; taking to the comb and brush as congenially as to the castinets…. (3.250)
Again, this is Delano's racism talking here; he thinks black people are naturally made to be servants. And he's completely, idiotically wrong; Babo isn't made to be anybody's servant. In fact, he's so little suited to being a servant that he's willing to kill, and to die, in order to avoid being one.
Quote #8
"This is an uncommonly intelligent fellow of yours, Don Benito, whispered Captain Delano across the table. (3.297)
Almost by accident, Delano stumbles on the truth. He's still racist (he thinks it's surprising that a black person can be intelligent) but he's managed to figure out that Babo is, in fact smart.
Quote #9
…he had determined to kill his master, Don Alexandro Aranda, both because he and his companions could not otherwise be sure of their liberty, and that to keep the seamen in subjection, he wanted to prepare a warning…(3.403)
Babo kills Aranda because he wants to make sure that Aranda won't be able to enslave them again. That seems like a reasonable solution to a reasonable fear. It's not clear whether you're supposed to sympathize with Aranda or not…but remember he's a slaveholder. Is his fate really unjust?